Some clocks may have multiple downstream users that need to request ahigher clock rate. Shared bus clocks provide a unique shared_bus_userclock to each user. The frequency of the bus is set to the highestenabled shared_bus_user clock, with a minimum value set by theshared bus. Drivers can use clk_enable and clk_disable to enableor disable their requirement, and clk_set_rate to set the minimum rate.